title: Homogeneous catalytic hydrogenation of amides to amines.
abstract: Hydrogenation of amides in the presence of [Ru(acac)3] (acacH=2,4-pentanedione), triphos [1,1,1-tris- (diphenylphosphinomethyl)ethane] and methanesulfonic acid (MSA) produces secondary and tertiary amines with selectivities as high as 93% provided that there is at least one aromatic ring on N. The system is also active for the synthesis of primary amines. In an attempt to probe the role of MSA and the mechanism of the reaction, a range of methanesulfonato complexes has been prepared from [Ru(acac)3], triphos and MSA, or from reactions of [RuX(OAc)(triphos)] (X=H or OAc) or [RuH2(CO)(triphos)] with MSA. Crystallographically characterised complexes include: [Ru(OAc-κ(1)O)2(H2O)(triphos)], [Ru(OAc-κ(2)O,O')(CH3SO3-κ(1)O)(triphos)], [Ru(CH3SO3-κ(1)O)2(H2O)(triphos)] and [Ru2(μ-CH3SO3)3(triphos)2][CH3SO3], whereas other complexes, such as [Ru(OAc-κ(1)O)(OAc-κ(2)O,O')(triphos)], [Ru(CH3SO3-κ(1)O)(CH3SO3-κ(2)O,O')(triphos)], H[Ru(CH3SO3-κ(1)O)3(triphos)], [RuH(CH3SO3-κ(1)O)(CO)(triphos)] and [RuH(CH3SO3-κ(2)O,O')(triphos)] have been characterised spectroscopically. The interactions between these various complexes and their relevance to the catalytic reactions are discussed.
authors.affiliation: EastChem, School of Chemistry, North Haugh, University of St. Andrews, St. Andrews, Fife, KY16 9ST, Scotland, UK.
authors.forename: Jacorien
authors.initials: J
authors.lastname: Coetzee
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Dodds
authors.forename: Jürgen
authors.initials: J
authors.lastname: Klankermayer
authors.forename: Sandra
authors.initials: S
authors.lastname: Brosinski
authors.forename: Walter
authors.initials: W
authors.lastname: Leitner
authors.forename: Alexandra M Z
authors.initials: AM
authors.lastname: Slawin
authors.forename: David J
authors.initials: DJ
authors.lastname: Cole-Hamilton
mesh_terms: D000577:Amides / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry; D006865:Hydrogenation; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry
chemical_list: D000577:Amides; D000588:Amines; D056831:Coordination Complexes; D012428:Ruthenium
keywords: amide hydrogenation; amines; catalysis; homogeneous catalysis; ruthenium